It is known that if an intervertebral disk is damaged, it can be removed and the space thereby produced can be filled with cortico-spongiose bone.
With this method, the vertebral bodies are first spread as far apart from each other as possible using a spreader. One special technique consists of placing wedge-shaped pieces--so-called dilators--between the two vertebral bodies, to spread them in step fashion out from each other. In turn, dilators with diameters that increase in each case by 1 mm are alternately inserted from the left and right from the posterior. After the greatest possible spreading has been achieved, the dilators are replaced by the above-mentioned cortico-spongiose bone.
This known technique has a disadvantage in that the bone is difficult to manipulate and bring into the correct position, with corrections nearly impossible. An additional disadvantage of this technique is that in the intervertebral space a rectangular or cylinder-shaped recess must be cut away or milled out, to insert the bone implants between the initially concave sides of the adjoining vertebral bodies. This is complicated, and also causes damage to the vertebral body.
For this, the invention affords a remedy. The invention has the task of creating an implant for the intervertebral space. Based on its specific shape and the method of insertion, it allows an extremely stable locking between the vertebral bodies, without damaging the surface of the bony cover plate of the vertebral body.
An additional task of the invention is to create an implant for the intervertebral space which can be put in without using dilators.